【作者】 李智慧；

【导师】 唐勇；

【作者基本信息】 燕山大学 ， 计算机应用技术， 2012， 硕士

【摘要】 随着图形学的发展以及3D动画的兴起，生物现象的真实模拟逐渐成为计算机图形学领域研究的热点。各种生物现象(如树皮、羽毛、毛发、毛皮等)结构复杂、特征各异，必须单独研究。国内外研究人员对大多数生物体体表都具有的鳞片状结构(或类似鳞片状结构)的模拟也开展了一些研究。在此基础上，对鱼体的真实感模拟进行研究，具有理论和实际意义。首先，鉴于曲面建模的快速性、灵活性特点，采用应用广泛的双三次Bezier曲面建模鱼体。将整个鱼体分为若干部分，通过调整Bezier曲面的控制点对各部分独立建模，减少整体建模的难度。根据鱼体的对称特性，通过左侧鱼体建模数据可得到右侧鱼体建模数据，实现鱼体的快速准确建模。其次，根据鱼鳞和鱼鳍的特点，分别设计其纹理合成单元。为消除纹理合成中易出现的接缝现象，对纹理合成单元进行无缝处理，实现其上、下、左、右无缝自拼接。在此基础上，利用Bezier曲面的u、v参数将鱼体Bezier曲面划分为四边形网格，并用u、v参数的跨度值和方向约束鱼体纹理合成中尺度和方向的变化，实现快速鱼体纹理合成。再次，为真实地表现鱼体表面几何细节和光泽，制作鱼鳞和鱼鳍纹理合成单元的法线图，使用法线贴图技术渲染鱼体。为模拟鱼体体表的色斑，设计鱼身第二层网格和色斑纹理合成单元，并设置随机函数，通过对随机函数的控制实现色斑形状和分布的随机动态显示。最后，在Windows平台上，使用VC++语言、专业三维图形API OpenGL以及可编程图形硬件语言Cg，实现鱼体的真实感模拟系统，对提出的方法进行实验验证。实验结果表明，本文方法能够逼真地模拟真实鱼体，展现其微小几何细节和丰富的色泽、色斑等体表特征。更多还原

【Abstract】 The simulation of biological phenomena is an important research aspect in ComputerGraphics. With the development of Computer Graphics and the rise of3D animation, therealistic simulation of biological phenomena has been becoming a hot spot. A variety ofbiological phenomena (such as bark, feathers, hair, fur and so on) have complex structuresand different characteristics, so the research on them must be done separately. Theresearchers in China and abroad have made some research on scales-like structures whichare common surface characteristics to many species of animals. On this base, the realisticsimulation of the fish has theoretical and practical significance.Firstly, considering the rapidity and flexibility of Surface Modeling and the great dealapplication of bicubic Bezier surfaces, this paper use bicubic Bezier surfaces to model thefish.In order to reduce the difficulty of modeling, we divide the fish into several parts, andmodel them individually by adjusting the control points of Bezier surfaces. According tothe symmetry of the fish, we use the Modeling data of the left side of the fish to get that ofthe right side of the fish, finishing the rapid and exact modeling of the whole fish.Secondly, according to the features of the fish scale and the fish fin, we designtexture synthesis units for them separately. In order to eliminate the seam phenomena intexture synthesis, we made seamless processing for them. Using the parameters u and v,we subdivide the Bezier surfaces of the fish into regular quadrilateral meshes, and use thedirection and the interval value of u and v to control that of the fish texture on the meshes,implementing the fish texture synthesis rapidly.Thirdly, in order to really display the geometry details and the gloss of the fish, wemake the normal maps of the scales texture unit and the fin texture unit, and render thefish by applying the Normal Mapping. We also design the second mesh on the fish bodyand the color spot texture unit to simulate the color spot on the fish body. By controllingrandom function, the shape and distribution of the color spot on the fish body can bedisplayed dynamically in real time.Finally, by using VC++, OpenGL and Cg on Windows platform, we design a realisticfish simulation system to validate the effectiveness of the methods proposed. Experimental results show that our methods can realistically simulate the real fish, displaying the smallgeometry details and the rich color, gloss and color spot.更多还原